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Multiply by 1-digit numbers: FAQ

Frequently asked questions about multiplying by 1-digit numbers.

How can we use the distributive property to multiply larger numbers?

The distributive property is a rule in math that lets us break apart a multiplication problem into smaller parts to make it easier to multiply.
For example, if we want to multiply 123×6, we can break 123 down into 100+20+3, and then use the distributive property to multiply each part by 6:
123×6=(100+20+3)×6=(100×6)+(20×6)+(3×6)=(600)+(120)+(18)=738
Try it yourself with these exercises:

How can we use area models to multiply larger numbers?

Similar to the distributive property, we can use area models to make multiplication easier. An area model is a way of visualizing a multiplication problem by drawing a rectangle and dividing it into sections. It can help us understand how different parts of the problem work together.
The following area model shows 3,538×5 broken into parts.
The image is not drawn to scale.
An area model using a rectangle of 4 unequal parts, all with a width of 5 but different lengths. From left to right, the parts are labeled A, B, C, and D, and the lengths, also from left to right, are 3000, 500, 30, and 8.
Try it yourself with these exercises:

Why do we need to learn how to estimate products?

Estimating products can help us check our work and get a rough idea of what the answer might be before we start multiplying.
Practice estimating products with this exercise:

Why is it important to learn different ways to multiply 1-digit by 2-, 3-, and 4- digit numbers?

Different methods may work better for different people, so learning multiple methods can help you find the one that works best for you. Understanding more than one way to solve a problem can deepen one's understanding of the mathematical concepts involved, as opposed to just memorizing one procedure.

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